Strong Photoacoustic Signal Enhancement by Coating Gold Nanoparticles with Melanin for Biomedical Imaging |
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| Authors: | Tatjana Repenko Anne Rix Alexander Nedilko Jonas Rose Alina Hermann Rostislav Vinokur Sheila Moli Roberto Cao‐Milàn Martin Mayer Gero von Plessen Andreas Fery Laura De Laporte Wiltrud Lederle Dmitry N Chigrin Alexander J C Kuehne |
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| Affiliation: | 1. DWI – Leibniz Institut für Interaktive Materialien e.V., Aachen, Germany;2. Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany;3. I. Physikalisches Institut (1A), RWTH Aachen University, Aachen, Germany;4. Laboratorio de Bioinorgánica, Facultad de Química Universidad de La Habana, La Habana, Cuba;5. IPF – Leibniz‐Institut für Polymerforschung Dresden e.V., Institute of Physical Chemistry and Polymer Physics, Dresden, Germany;6. Cluster of Excellence Center for Advancing Electronics Dresden (cfaed), Technische Universit?t Dresden, Dresden, Germany |
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| Abstract: | Photoacoustics is a powerful biomedical imaging and detection technique, because it is a noninvasive, nonionizing, and low‐cost method facilitating deep tissue penetration. However, suitable contrast agents need to be developed to increase the contrast for in vivo imaging. Gold nanoparticles are often discussed as potential sonophores due to their large absorption cross‐section and their tunable plasmon resonance. However, disadvantages such as toxicity and low photoacoustic efficiency in the tissue transparency window prevail, preventing their clinical application. As a result, there remains a strong need to develop colloidal photoacoustic contrast agents which absorb in the tissue transparency window, exhibit high photoacoustic signal, and are biocompatible. Here, a facile synthetic approach is presented to produce melanin shells around various gold nanoparticle geometries, from spheres to stars and rods. These hybrid particles show excellent dispersability, better biocompatibility, and augmented photoacoustic responses over the pure melanin or pristine gold particles, with a rod‐shape geometry leading to the highest performance. These experimental results are corroborated using numerical calculations and explain the improved photoacoustic performance with a thermal confinement effect. The applicability of melanin coated gold nanorods as gastrointestinal imaging probes in mouse intestine is showcased. |
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| Keywords: | contrast agents core‐shell particles intestinal imaging photothermal thermal confinement |
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